Thermodynamic and economic multi-objective optimization of geothermal and solar combined power system
Year: 2025
Type: article
Abstract: • Developed a dual-pressure ORC for high-altitude solar–geothermal hybrid power. • Synergistic solar–geothermal heat input enhanced thermal efficiency. • NSGA-II identified Pareto-optimal trade-offs between efficiency and cost. • DP-ORC with R1233zd(E) reaches 13.18% thermal efficiency. • Minimum LCOE is 0.162 $/kWh under optimized settings. To address the challenge of effectively utilizing Tibet’s abundant solar and geothermal resources for local power supply, this study proposes a novel geothermal-solar dual-pressure organic Rankine cycle (DP-ORC) system tailored for high-altitude applications. The research aims to investigate how key thermodynamic parameters-namely low- and high-pressure evaporation pressures and superheat-affect both energy conversion efficiency and economic feasibility of the system. Six environmentally friendly pure working fluids (e.g., R1233zd(E), R600) are evaluated through detailed parametric analysis. A multi-objective optimization using NSGA-II is conducted with system thermal efficiency and levelized cost of electricity (LCOE) as competing objectives. The results demonstrate that increasing both low- and high-pressure evaporation pressures significantly improves net power output and system efficiency, while lower superheat enhances exergy performance. Among all candidates, R1233zd(E) exhibits the best overall trade-off, achieving a thermal efficiency of 13.18% and the lowest LCOE of 0.162 $/kWh. Component-level cost and exergy analysis further reveal that the condenser contributes 52.72% of total system irreversibility, and solar collectors account for 42.3% of the capital cost. This work provides a systematic framework for the thermo-economic optimization of hybrid renewable systems in resource-rich but infrastructure-limited regions, demonstrating the superior performance of R1233zd(E) in balancing efficiency and cost.
Source: Results in Engineering
Authors: Zhong Ge, Xin Chen, Jian Li, Mingzhe Yu, Fubin Yang
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,940
Funders: National Natural Science Foundation of China, Natural Science Foundation of Yunnan Province, Beijing Institute of Technology Research Fund Program for Young Scholars, National Key Research and Development Program of China, National Key Research and Development Program of China Stem Cell and Translational Research
Awards: G461574878, G6367433548, G7549327774
OpenAlex ID: W4416266528